Studies are being undertaken with mouse 3T3 cells in culture, SV- 40-transformed 3T3 cells, and revertant cells (contact-inhibited, SV40- transformed 3T3 cells) to determine what macromolecular changes occur at the cell surface as a result of viral transformation and which chemical components at the surface may mediate contact inhibition of growth and movement. Two different selective procedures have been used to yield revertants. The use of Ca ion and/or Mg ion chelating agents are being studied to release cells from surfaces while hopefully minimizing the breakdown of surface membrane macromolecules. Collagen, mucopolysaccharides, and other glycoproteins--components at the surfaces of cells--will be analyzed quantitatively for any correlation with growth control. Surface glycoproteins will be separated by gel electrophoretic methods. The polysaccharide portion of glycoprotein fractions will be examined for sugar composition, chain length, and microheterogeneity. Attempts will be made to artificially induce contact inhibition by treating cultures of transformed cells with surface components from 3T3 or revertant cells.